An AFM’s cantilever has a fine tip that can be used to map surfaces at the nanoscale. The movements of the tip are monitored using laser light reflected from the cantilever. If you could manufacture a hollow cantilever and pass a liquid through it, as happens in a fountain pen, then you could kill two birds with one stone. In addition to mapping surfaces, you could also use it to make highly localized measurements of the concentration of specific chemicals. This concept was the brainchild of Dr Peter Schön, a researcher at the University of Twente (Enschede, Netherlands) who leads the Enabling Technologies Strategic Research Orientation at the MESA+ Institute for Nanotechnology.